feat(cketh): add the SweeperFunding withdrawal-request variant

rs/ethereum/cketh/minter/cketh_minter.did

@@ -242,7 +242,6 @@ type MinterInfo = record {
     evm_rpc_id : opt principal;
 };
 
-
 type GasFeeEstimate = record {
     // Maximum amount of Wei per gas unit that the transaction is willing to pay in total.
     // This covers the base fee determined by the network and the `max_priority_fee_per_gas`.
@@ -570,6 +569,14 @@ type Event = record {
             from_subaccount : opt blob;
             created_at: opt nat64;
         };
+        AcceptedSweeperFundingRequest : record {
+            withdrawal_amount : nat;
+            destination : text;
+            ledger_burn_index : nat;
+            from : principal;
+            from_subaccount : opt blob;
+            created_at: nat64;
+        };
         CreatedTransaction : record {
             withdrawal_id : nat;
             transaction : UnsignedTransaction;

rs/ethereum/cketh/minter/src/dashboard.rs

@@ -361,6 +361,13 @@ impl DashboardTemplate {
                         created_at: Some(req.created_at),
                     }
                 }
+                WithdrawalRequest::SweeperFunding(req) => DashboardWithdrawalRequest {
+                    cketh_ledger_burn_index: req.ledger_burn_index,
+                    destination: req.destination,
+                    value: req.withdrawal_amount.into(),
+                    token_symbol: CkTokenSymbol::cketh_symbol_from_state(state),
+                    created_at: Some(req.created_at),
+                },
             })
             .collect();
         withdrawal_requests.sort_unstable_by_key(|req| Reverse(req.cketh_ledger_burn_index));

rs/ethereum/cketh/minter/src/dashboard/tests.rs

@@ -884,12 +884,16 @@ fn should_display_reimbursed_requests() {
                                 },
                             );
                         }
+                        WithdrawalRequest::SweeperFunding(_) => {
+                            unreachable!("sweeper funding is never reimbursed")
+                        }
                     }
                 } else {
                     apply_state_transition(
                         &mut state,
                         &EventType::QuarantinedReimbursement {
-                            index: ReimbursementIndex::from(&req),
+                            index: ReimbursementIndex::try_from(&req)
+                                .expect("BUG: this test's fixtures are all user withdrawals"),
                         },
                     )
                 }

rs/ethereum/cketh/minter/src/endpoints.rs

@@ -489,6 +489,14 @@ pub mod events {
             from_subaccount: Option<[u8; 32]>,
             created_at: Option<u64>,
         },
+        AcceptedSweeperFundingRequest {
+            withdrawal_amount: Nat,
+            destination: String,
+            ledger_burn_index: Nat,
+            from: Principal,
+            from_subaccount: Option<[u8; 32]>,
+            created_at: u64,
+        },
         CreatedTransaction {
             withdrawal_id: Nat,
             transaction: UnsignedTransaction,

rs/ethereum/cketh/minter/src/lib.rs

@@ -45,3 +45,10 @@ pub const EVM_RPC_ID_PRODUCTION: Principal =
     Principal::from_slice(&[0, 0, 0, 0, 2, 48, 0, 204, 1, 1]);
 pub const EVM_RPC_ID_STAGING: Principal = Principal::from_slice(&[0, 0, 0, 0, 2, 48, 0, 161, 1, 1]);
 pub const CKETH_LEDGER_MEMO_SIZE: u16 = 80;
+
+pub const CKETH_FEE_SUBACCOUNT: [u8; 32] = {
+    let mut subaccount = [0_u8; 32];
+    subaccount[30] = 0x0f;
+    subaccount[31] = 0xee;
+    subaccount
+};

rs/ethereum/cketh/minter/src/main.rs

@@ -32,7 +32,7 @@ use ic_cketh_minter::state::audit::{Event, EventType, process_event};
 use ic_cketh_minter::state::eth_logs_scraping::{LogScrapingId, LogScrapingInfo};
 use ic_cketh_minter::state::transactions::{
     Erc20WithdrawalRequest, EthWithdrawalRequest, Reimbursed, ReimbursementIndex,
-    ReimbursementRequest,
+    ReimbursementRequest, SweeperFundingRequest,
 };
 use ic_cketh_minter::state::{
     STATE, State, lazy_call_ecdsa_public_key, mutate_state, read_state, transactions,
@@ -407,7 +407,9 @@ async fn withdrawal_status(parameter: WithdrawalSearchParameter) -> Vec<Withdraw
                 withdrawal_id: *request.cketh_ledger_burn_index().as_ref(),
                 recipient_address: request.payee().to_string(),
                 token_symbol: match request {
-                    CkEth(_) => CkTokenSymbol::cketh_symbol_from_state(s).to_string(),
+                    CkEth(_) | SweeperFunding(_) => {
+                        CkTokenSymbol::cketh_symbol_from_state(s).to_string()
+                    }
                     CkErc20(r) => s
                         .ckerc20_tokens
                         .get_alt(&r.erc20_contract_address)
@@ -417,12 +419,16 @@ async fn withdrawal_status(parameter: WithdrawalSearchParameter) -> Vec<Withdraw
                 withdrawal_amount: match request {
                     CkEth(r) => r.withdrawal_amount.into(),
                     CkErc20(r) => r.withdrawal_amount.into(),
+                    SweeperFunding(r) => r.withdrawal_amount.into(),
                 },
                 max_transaction_fee: match (request, tx) {
-                    (CkEth(_), None) => None,
+                    (CkEth(_) | SweeperFunding(_), None) => None,
                     (CkEth(r), Some(tx)) => {
                         r.withdrawal_amount.checked_sub(tx.amount).map(|x| x.into())
                     }
+                    (SweeperFunding(r), Some(tx)) => {
+                        r.withdrawal_amount.checked_sub(tx.amount).map(|x| x.into())
+                    }
                     (CkErc20(r), _) => Some(r.max_transaction_fee.into()),
                 },
                 from: request.from(),
@@ -832,6 +838,21 @@ fn get_events(arg: GetEventsArg) -> GetEventsResult {
                     from_subaccount: from_subaccount.map(LedgerSubaccount::to_bytes),
                     created_at,
                 },
+                EventType::AcceptedSweeperFundingRequest(SweeperFundingRequest {
+                    withdrawal_amount,
+                    destination,
+                    ledger_burn_index,
+                    from,
+                    from_subaccount,
+                    created_at,
+                }) => EP::AcceptedSweeperFundingRequest {
+                    withdrawal_amount: withdrawal_amount.into(),
+                    destination: destination.to_string(),
+                    ledger_burn_index: ledger_burn_index.get().into(),
+                    from,
+                    from_subaccount: from_subaccount.map(LedgerSubaccount::to_bytes),
+                    created_at,
+                },
                 EventType::CreatedTransaction {
                     withdrawal_id,
                     transaction,

rs/ethereum/cketh/minter/src/state.rs

@@ -371,6 +371,10 @@ impl State {
                 .checked_sub(tx.transaction().amount)
                 .expect("BUG: withdrawal amount MUST always be at least the transaction amount"),
             WithdrawalRequest::CkErc20(req) => req.max_transaction_fee,
+            WithdrawalRequest::SweeperFunding(req) => req
+                .withdrawal_amount
+                .checked_sub(tx.transaction().amount)
+                .expect("BUG: funded amount MUST always be at least the transaction amount"),
         };
         let unspent_tx_fee = charged_tx_fee.checked_sub(tx_fee).expect(
             "BUG: charged transaction fee MUST always be at least the effective transaction fee",

rs/ethereum/cketh/minter/src/state/audit.rs

@@ -74,6 +74,11 @@ pub fn apply_state_transition(state: &mut State, payload: &EventType) {
                 .eth_transactions
                 .record_withdrawal_request(request.clone());
         }
+        EventType::AcceptedSweeperFundingRequest(request) => {
+            state
+                .eth_transactions
+                .record_withdrawal_request(request.clone());
+        }
         EventType::CreatedTransaction {
             withdrawal_id,
             transaction,

rs/ethereum/cketh/minter/src/state/audit/tests.rs

@@ -97,7 +97,7 @@ impl GetEventsFile {
         use crate::eth_logs::EventSource;
         use crate::state::TransactionStatus;
         use crate::state::audit::EventType as ET;
-        use crate::state::transactions::EthWithdrawalRequest;
+        use crate::state::transactions::{EthWithdrawalRequest, SweeperFundingRequest};
 
         fn map_event_source(
             CandidEventSource {
@@ -315,6 +315,21 @@ impl GetEventsFile {
                     from_subaccount: from_subaccount.and_then(LedgerSubaccount::from_bytes),
                     created_at,
                 }),
+                EventPayload::AcceptedSweeperFundingRequest {
+                    withdrawal_amount,
+                    destination,
+                    ledger_burn_index,
+                    from,
+                    from_subaccount,
+                    created_at,
+                } => ET::AcceptedSweeperFundingRequest(SweeperFundingRequest {
+                    withdrawal_amount: withdrawal_amount.try_into().unwrap(),
+                    destination: destination.parse().unwrap(),
+                    ledger_burn_index: map_nat(ledger_burn_index),
+                    from,
+                    from_subaccount: from_subaccount.and_then(LedgerSubaccount::from_bytes),
+                    created_at,
+                }),
                 EventPayload::CreatedTransaction {
                     withdrawal_id,
                     transaction,

rs/ethereum/cketh/minter/src/state/event.rs

@@ -5,7 +5,7 @@ use crate::lifecycle::{init::InitArg, upgrade::UpgradeArg};
 use crate::numeric::{BlockNumber, Erc20Value, LedgerBurnIndex, LedgerMintIndex};
 use crate::state::transactions::{
     Erc20WithdrawalRequest, EthWithdrawalRequest, Reimbursed, ReimbursementIndex,
-    ReimbursementRequest,
+    ReimbursementRequest, SweeperFundingRequest,
 };
 use crate::timed_sized_map::Timestamp;
 use crate::tx::{Eip1559TransactionRequest, SignedEip1559TransactionRequest};
@@ -182,6 +182,9 @@ pub enum EventType {
     /// durable even across an ungraceful trap (unlike the pre-upgrade snapshot).
     #[n(26)]
     AutomaticDepositReceived(#[n(0)] AutomaticDeposit),
+    /// The minter burned ckETH from its fee subaccount to top up the sweeper address with gas.
+    #[n(27)]
+    AcceptedSweeperFundingRequest(#[n(0)] SweeperFundingRequest),
 }
 
 /// Full snapshot of the ckERC20 deposit address registry. Carries the limits in